Pulse Forming Network Fault Limiting With Coupled Inductor Cooling
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Solution Overview
Problem
Conventional electromagnetic DC pulse power systems are vulnerable to damage during fault events, such as short circuits, due to peak current levels exceeding component capabilities, leading to irreversible damage.
Innovation Solution
The implementation of a fault current limiting (FCL) circuit within the pulse forming network (PFN) module, which includes a storage inductor with a primary winding and a magnetically coupled secondary winding, allows for controlled impedance adjustment during fault events, reducing fault current and distributing fault energy across multiple PFN modules to prevent component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional PFN circuits are used to generate high power output, then power capability is improved, but vulnerability to fault damage increases
Solution Approach 1:
An FCL circuit is introduced as an intermediary component between the PFN circuit and the fault condition. The FCL circuit includes a series switching device and reactive impedance that act as a mediator to limit fault current and protect the PFN circuit from direct exposure to fault energy, thereby resolving the contradiction between high power capability and fault resistance
Solution Approach 2:
The FCL circuit is pre-configured with switching devices and reactive impedance elements before a fault occurs. When a fault is detected, the switching device is activated in advance to insert the protective impedance, preventing the fault from directly affecting the PFN circuit. This preliminary preparation allows the system to maintain both high power output capability and reliability
2Reliability
If fault protection circuits are added to PFN modules, then reliability is improved, but device complexity increases
Solution Approach 1:
The fault protection function is segmented into modular FCL circuits that can be independently added to each PFN module. Each FCL circuit is a self-contained unit with switching devices and reactive impedance, allowing reliability to be improved without requiring complete redesign of the entire PFN system, thus managing device complexity
Solution Approach 2:
The FCL circuit is designed to perform multiple functions: normal operation mode, fault limitation mode, and energy dissipation mode. By making the protection circuit multi-functional, the system achieves improved reliability without proportionally increasing complexity, as the same components serve multiple purposes depending on operational conditions
3Object-affected harmful factors
If reactive impedance is inserted during fault events, then fault current limitation is improved, but power loss increases
Solution Approach 1:
The reactive impedance in the FCL circuit is inserted periodically or transiently only when fault conditions are detected, rather than being continuously present. The switching device activates the protective impedance during fault events and deactivates it during normal operation, thereby limiting fault current while minimizing power loss during normal power delivery
Solution Approach 2:
The system dynamically changes the impedance parameter of the FCL circuit based on operational conditions. During normal operation, the impedance is minimal or zero to avoid power loss. During fault events, the impedance parameter is changed to a high value to limit fault current, thus resolving the contradiction between fault current limitation and power loss
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The FCL circuit effectively limits fault currents and distributes fault energy, reducing the risk of component damage and minimizing system size and weight while maintaining high power output capabilities.
Implementation Method 1
The FCL circuit includes a secondary winding that is magnetically coupled with the primary winding. The FCL circuit is configured to receive fault energy existing in the PFN circuit during a fault event.
Data Source
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AI summary
An electromagnetic direct current (DC) power system includes a plurality of pulse forming networks (PFN) modules. Each pulse forming network (PFN) module includes a PFN circuit, a fault current limiting (FCL) circuit and a cooling system. The pulse PFN circuit is configured to generate a pulsed DC output power. The PFN circuit further includes at least one energy storage inductor with primary winding having a primary winding inductance that controls a primary impedance of the PFN circuit. The FCL circuit includes a secondary winding that electrically communicates with the primary winding. The FCL circuit is configured to receive fault energy existing in the PFN circuit during a fault event. The cooling system is configured to cool at least one of the primary winding and the secondary winding, and remove a portion of the fault energy.